Train control



Nov. s, 1928. 1,691,006-

1 C. S. BUSHNELL TRAIN .CONTRO L Filed Jul 25, 1924 25 21 as as as Patented Nov. 6, 19 28.

11 m TED (STATE 5 P A'Tf-E \ioFFieE;

V ,oHABLESs, KELLaQF-BLOCHESTER, NEW yoRK, ASSIGNORVTQGENE BAL, RAILWAY SIGNALQQMRANIOF ROCHESTER, HEW YORK.

minim oonrrnon V This invention relates to automatictrain control systems, and more particularly -toimprovements in car-carried control apparatus for such systems whereby continuous opera-: 5 -tion of the drivingmechanism of such-appa- 'ratus may beinsured. Intrain control practice, ycontrolinfluences corresponding to 'traific conditons ahead are usually communicated by si'iitablemeansfrom the trackwayto control apparatus carried-on the vehicle. 'Thiscontrol apparatusordinarily includes severalydevices, including a speed responsive device, which devices are driven fromthe car Wheels by suitable means; In order that thiscontrolapparatus may bereliabl and mayat all'times reflect the speed and progress of-thetrai-n, it is desirable that thedrive or'transmission for this speed'responsive device and the other driven control devices be checked, so that any failure of such driving apparatus-may be brought tothe attention'of the engineerortrain operator. A

It is an object of this invention-toprovide' means for. checking the drive of the carcarried control-apparatusandfor bringing the vehicle to a stopif such drive should fail.

Further objects and'advantages of the invcntion Willbe pointed out or will become apparent as the description progresses. so

oi" a system embodying 'this invention has been shown'in' a diagrammatic and simplified manner.

The system shown is'of the type which acts to imposemore and more restrictive speeds as the vehicle progresses from a point at which certain control influences are received,

although it is to be understood that many other types of control systems employing de- 40 vices drivenfrom the car wheels may be usedin connection with the present invention.

In theparticular system shown, a main car relay MRihavingtwo movable contact fingers 1 and2 isjprovided. -Thisrelay may be of 4.3 the two-position singlephase type, asshown.

but any othertype o'f relay ma-ybe employed if desired. In the'type offrelay shown, the contact fingers 1 and'2 arepreterably biased by springs or weights toassume a definite position uponde-energization of the relay windequipment may includean amplifying device,

used forms no part-of the present invention.

:Inthe-drawingathe ear-carried apparatus 'tri'fuge G; This centrifuge comprises; atfixed galforce acting uponthelinks and weights 210 '1924 Serial N0. 1728, 186.

tings. These contact fingers E1 and-Qarealso preferably' mounted onlvertically arranged axes-so 'asrtobe unaffectedby the vibrationor swaying of 4 the train. It T is assumed that :the

mainirelay MB is connected by meanszofthe Wl16S'3 and l'tosuitable receivingdevices located'on'the vehicle, and arrangedx'to respond to control influences transmitted :from suit- I able trackway apparatus. The receivingand the input cirouitto said amplifiying'dd vice mayiberesonatedi by means ota condenser ifdesired. v I I The particulartrackway apparatus and: the associated car-carried receiving devices may be of any suitable type and 'haveforconvenience not'beenillustratedinithe drawings, as the 'operationof such apparatusanddevices is well known to 'those skillediinithesa-rt,

and asthe'specific'form oftransmittingmeans A 1 drive shaft 5 is provided, L and isigeared or otherwise-suitably driven ffromithe 'wheels and axles of the vehicle. This shafft carries vice. The speed responsive devioemay come prise any one of a number-of suitable types. In: the: embodiment chosen fortthepurpose of illustration,- a simplified speed responsive device has'been shown, taking'the form'of :arcencollar"? and a mo vable collar 8, urged 5 apart by aspring 9,the collar 8 beingdrawni-downwardupon rotation OT thG'-Sh2ft"5?by centrifuand 11. The eollar8'engagesan arm 12,:fizredly secured to speed shafts 13, as shown, so

that'the shaft 134s rocked in proportion'to the speed atwhich the vehicleistraveling. Itshoukl be noted that the :fixed: collar Trend 90 the Worm gear'6 are intimately. associated, preferably being made integral, so "that; the possibility of a break in'the drivingzmechanism between thisawormgean 6 andathecentri fuge G is very remote.

. The'wor'm gear 6 operates the distance shaft 14 through a train of" gears and an: electrically operated gear engaging arm 15, as shown. Thevarm I5 is normally held in the disengaged position by means of-the camsstarter magnet 100 apparatus.

CS, and when this magnet is de-energized, the spring 16 places the arm 15 in the engaged position. The distance shaft 14: is driven through a mutilated gear 17 and is returned to its normal position by a spring 18 upon the disengagement of the gear train ust described.

The speed shaft 13 and the distance shaft 14: may carry any number of cams or other devices for operating the car-carried control In the simplified embodiment shown, a single speed cam 19 is provided on the speed shaft 13, and a distance ca1n20 and permissive speed cam 21 are provided on the distance'shaft 14. p The speed cam 19 operates the resilient contact fingers 22, biased to. the opened position, the cam 19 being designed to openthese contact fingers at speeds from zero to 15 miles per hour only. The distance cam 20 operates the resilient contact fingers 23 similar to thosejust described, and is designed to close these contact fingers as soon as the distance shaft 1 1 is operated. The permissive speed cam 21 operates oneend of a floating lever 24, the other end of which is moved by the lever 25, in proportion to the rocking of the speed shaft- 13. It is evident that the movement of an intermediate point on this floating lever 24 will be determined by a function of the vehicle speed and distance of travel from the point at whichthe distance shaft 14: is initiated. The floating lever 24 operates a contact sector 26 through a link 27,

thiscontact cam being normally biased by the spring 28. The sector 26 operates the resilient contact fingers 29, which are normally biased to their open position, and allows these contactfingersto open under certain condiable contact finger 30, and a stationary front contact, conventionally represented by the arrow 31. The contact finger 30 is biased to disengage the front contact 31 a predetermined time after the de-energization of the windings of the relay GR. 7

Suitable means are provided for applying the brakes of the train in response to control influences. These means may take the form of a valve for venting the loralre pipe directly, or may-consist of a device for operating the regularengineens brake-valve. In the sink plified form shown, an -electro-pneuinatic valve EPV is provided, it being assumed that th1s electro-pneumatic valve will act in some the letters B and C have been used to represent the opposite poles of a source of electrical energy which may be the terminals of a battery. r

V Operation-Before explaining the operation of the check for the control apparatus drive which comprisesthe present invention, a brief description of the operation of the sirnpliiied and typical train control system shown will be given. V

in the usual train control system, dangerous trallic conditions ahead, such as a train, a broken track rail, an open switch or other hazard in the block in which the train is located, or in the next block in advance, are usually arranged to so af ect the receiving de- .vices as to cause the de-energizationof the hour but not excessive, the main relay MR will be energized, attracting its contact lingers 1 and 2. The contact finger 1 closes a circuit to the cam starter magnet CS through the con-- tact lingers 22 of the speed cam 19, and the contact linger 2 of the main relay MR closes a circuit to the control relay CR, which circuits are obvious from the drawings. The .energisation of the cam starter magnet CS maintains the gear train di. I

distance shaft 14: is therefor in its initial biased position as shown. The energization of the control relay CR closes the front con tact 31 of this reiav, so maintaining an energizing circuit to the electro-pneuinatic valve EPV through the contact linger 29 of the sector 26, which circuit is obvious from the drawings, lVith the electro-pneumatic valve EPV energiaedl the train mayproc'eed in the clear block for reasons heretofore given.

, As the speed of the train increases, the speed shaft 13 movesthe sector 26 through. the arm 25, the floating lever 24c and the link 27, and if a maximum speed limit of, say 60 miles per hour, is exceeded, the contact fingers 29 are opened. and the energizing circuit to the electric-pneumatic valve EPV isbrolzen, causin an automatic brake application which con tinues. until the train speed has been reduced below the maximum speed limit assur n he 60 mil s ner hour, when the electro-pncngaged, and the.

e s main energized bythe closing If the train enters ablock in which caution traificconditions exist, the main relay MR becomes de-energized, retracting its contact fingers 1 and 2, andso'openin'g the front contacts of these fingers. The opening of the front contact of finger 1 de-cnergizes the cam starter magnet CS, causing the. engagement of the gear train and thestarting of the distance shaft 14. As soon as-the distance shalt 1 1 starts, the cam 20 closes its contact fingers 23, energizing the control relay CR througl'i a circuit which includes these fingers 23 and the Wire 33 as shown. As the distance shaft 4.- continues to rotate, the permissive speed cam 21 moves the floating lever 2 1, imposing more and more restrictive speed limits through the 01111126 and its associated contact fingers 29. After the distance shaft Ll has been rotated through approximately 180 its further rotation will be prevented by the mutilated por' tion of the mutilated gear, and minimum speed limit will be set up by the permissive speed cam 21. This minimum s eed limit assumed. in the present embodiment to be 20 miles per hour. If the restrictive speed limit is exceeded, the sector 26 will open its contact fingers 29, de-energizing the electropneumatic valve EPV and causing anautomatic brake application which continues until the train speed has been reduced to a value below that of the restrictive limitwhich is set up by the permissive speed cam and associated mechanism. The opening ofthe front contact or finger 2 01'' then'iain relay MR breaks a circuit to the control relay CR, but this control relay is immediately re-energized through the contact finger 23 of the cam 20 as explained above, and as this control relay GR is slow acting. its contact fin 30 will not be retracted by this momentary d e-energize tion of its windings.

-When traffic conditions become more favorable, the main relay MB is re-energized, attracting its contactfingers land 2, re-energizing the cam starter magnet CS and allowing the distance shaft latto assume its initial position, whereupon the restrictive control through the sector 26 is removed, and the train may proceed at speed. Thecontact fin-' gers 23 of the distance cam 20 are opened, but the control relay GR is maintained energized through the contact" finger 2 of themain relay MR.

Referring now particularly to the operation of the check for the transmission to the control apparatus, which is the essential part of the present invention assume that a tram equipped with the apparatus described is proceeding under clear tratlic conditions,

and that the drive shaft becomes disengaged from the axles of the vehicle by reason of a break in this shaft or for any other reason. The centrifuge G will immediately assume its zero miles per hour position, opening the contact finger 22 of the speed cam 19 and thus de-energizing the cam starter magnet CS. The de-energization of the cam starter magnet GS will cause the gear train to be engaged, but no motion of thedistance shaft 14 will resulttor the reason that no power is applied from the drive shaft 5. v The contact fingers 23 operated by the distance cam will therefore remain open.

Now assume that the train under consideration'with its control apparatus in the condi tion just described enters a block in which caution trafiic conditions exist. The main relay MR will be de-encrgi'zed, retracting its contact fingers 1 and 2. The retracting of the contact finger 2. of the main relay MR will open the energizing circuit to the control relay CR, de-energizing the windings of this relay'and causing the retraction of 1ts contact finger after a given period of time. When the contact finger 30 of the control relay CR disengages its front stationary contact 31, the energizing circuit to the electro-pneumatic valve EPV will be broken, and an automatic train to a stop. As this automatic stopwill be immediate, and will not be preceded by the usual tapered speed restriction described brake'application will result, bringing the above, the engineer or train operator will be aware of the fact that the drive shaft of the control apparatus is out of order, and'will probably out out the automatic train control apparatus by'operat-ing a suitably sealed or otherwise protected cut-out device, the

operation of which must be explaineda'nd excused at theend ofthe run. In such. cut-out device is not provided,.the train must remain at astop until trafiic conditions ahead'become more favorable, when the train may proceed with automatic stop control, that is, whenever the train enters a caution or a danger block, it is brought to a stop at once by the de-energization of the control relay CR the electro-pneumaticvalve EPV, controlled by the contact finger 2 of the main relay MR. Now assume that the train under cousideration is proceeding under caution tratfic conditions, that is, with themain relay MR'deot the cam 20. The speed arm 12 1's raised I by the spring 9, causing the shaft 13 to as sumetits zero miles per hour position, and causing the speed cam 19 to open its contact fingers 22. As the main car relavMR is already de-energized and'its contact finger 2 is in the open position, the opening ofc'o'ntact finger 23 of the cam 20 will cause the de- Ill apparatus embodying the present invent on comes to a stop under clear traffic conditions, lVhen the train speed 1s reduced to miles per hour, the contact fingers 22 ot the speed cam 19 are opened, causing. the de-energgization of the cam starter magnet CS and the consequent initiation of the distarce shaft 14. As the train comes to a stop, the distance shaft 14 will be rotated a slight amount, causing the cam20 to close its contact finger s3, and maintaining these contact'fingers closed so long" as the train is at a stop. Now assume that while the train under consideration is at a stop, the traffic conditions in the block in which the train is located change from clear to caution or danger by reason of a train hacking into the block, the breaking; of a rail, the opening of a switch or any other dangerous condition. The main relay MR will immediately be deenernized, retracting its contact tinsel-s 1 and core 1 0 1e Oibfiu.lnt f.lv. 2 Th r t act ng ftl c "i c d j 1 ]ll have no effect as the contact fingers 22 in series with the contact finger 1 are already opened. The retracting; of the contact finger 2 of the main relay MR will also have no effect, as the control relay GR is maintained energized through a circuitincluding the contact finger 23 of the distance cam 20. The

train may now proceed in a caution block under the restrictive control of the permissive speed cam 21 as described above.

Assume now that a train proceeds in a clear block at a low speed, below 15 miles per hour, for a comparatively longdistance. As soon as the train speed drops below 15 miles per hour, the speed cam 19 will operate to open its associated contact fingers 22, (ls-energizingthe cam starter magnet CS and starting the distance shaft 14. When the distance shaft 1%. has revolved through 180, the permissive speed cam 21 will impose minimum speed limit, assumed to be 20 miles per hour. It should be noted that as the train speed again increases, the cams starter magnet C will be 're-energized at 15 miles per hour and the distance Shaft 14 will be returned to its initial. position before the train speed reaches 20 miles per hour. It is clear from the above that a train cannot be permanently restricted to speed by reason of the fact th di tance shaft 14 is in its extreme run down position.

It is to be understood that the specific checlr. for the driving mechanism which forms the present invention could be applied to many different types of train control systems and that such train control systems may include by sai not shown and described in the present embodiment without departing from the spirit of the present invention. For instance, a polyphase car relay may be employed, imposing different speed restrictions under caution and danger traflic conditions; means may also be provided for permitting; the vehicle to proceed with either end leading, or many other additions or modifications which are optional rather than essential may be made.

l Vhat it is desired to secure by Letters Patent is:

1. In automatic train control system, vehicle carried brake control apparatus inclnc g a restrictive speed device imposing; a w:ictive brake control in response to unfavorable traiiic conditions ahead, means-for driving elements of said restrictive speed device in accordance with the motion of the vehicle, means for imposing a bralce applicaif said driving means stops, and further means speed initiated and operated in accordance with the train, for preventing said brake appli ation ifsaid driving means has stopped because of a lack of m n of the vehicle.

In an automatic train control system, ve-

hicle carried apparatus comprising a control mean esponsive to influences corresponding to t Le conditions ahead, a restrictive speed device having an element driven in accord-- ance with the progress of the vehicle. said rest 'ctive speed device being initiated by said control means and acting to impose restrictive speeds under unfavorable traffic conditions ahead, and further i'neans, having part-s automatically operated in accordance with progress of the train, for imposing a stop under unfavorable traflic conditions ahead only if said driven element stops while said vehicle is in motion. I

3. In an automatic train control system, ve hicle carried control apparatus comprising a main relay controlled'by influences corresponding' to traiiic conditions ahead, a restr ctive speed device driven inaccordance vith the motion of the vehicle, a brake control device, normally,controlled by said restrictive speed device, and means for transfe if g the control of said brake control device to said -main relay if the driving means for said re- 1 a brake applying means, normally controlled restrictive speed device, an 1 spending to traflic conditions ahead, a main control means and said speed governed d normally acting to control said c -ctive'speed device, and said distance governed device acting to transfer the controlof said brake applying means to said main control device under unfavorable traffic conditions ahead, onl if said driving means hecome inactive w ile the vehicle is in motion.

sponding to traffic conditions ahead, and acontrol relay for actuating said brake applying device from said main relay under favorable traffic conditions ahead if said driv ing means stops While the vehicle is in motion, said control relay being inactive if said driving means stops due to a stop of the vehicle.

6. In an automatic train control system, vehicle carried control apparatus comprising, a restrictive speed device, means for driving said restrictive device in accordance with the travel of the vehicle, a brake applying device, normally controlled by a circuit including a contact of said restrictive speed device, a main relay controlled in response to infiuences corresponding to trafiic conditions ahead, and a control relay for breaking said circuit to said brake applying device, said control relay being controlled alternatively by a circuit including contacts of said main relay and contacts of a distance governed element associated with said control device.

7. In an automatic train control system, vehicle carried brake control apparatus comprising a brake applying device, normally controlled by a restrictive speed device, means for driving said restrictive speed device, when initiated, in accordance with the travel of the vehicle, control means for initiating said restrictive speed device when influences corresponding to unfavorable traffic conditions are received from the trackway,

and means for causing an immediate operation of said brake control apparatus 1f the drive of said restrictive speed device stops while the vehicle is travelllng under unfavorable trafiic conditions, and means for preventing such brake application if the drive stops under favorable trafiic conditions.

8. In an automatic train control system, a,

normally energized brake applying device adapted to cause an automatic brake application when de-energized, a restrictive speed 'devlce including a speed responsive element and a distance operated element, both of said elements being driven in accordance with the travel of the vehicle, said restrictive speed device acting when initiated to de-energize said brake applying device if the vehicle speed exceeds a predetermined value, a main relay, energized in accordance With favorable traffic conditions and de-energized in response to unfavorable traffic conditions ahead, and acting when de-energized'to initiate said restrict-i'vespeed device, a 'control relay, acting when de-energized to de-energize said brake applying device, said control relay being energized by the energization of said main relay and being energized if said distance element of said restrictive speed device isinitiated, and meansfor initiating said distance element of said restrictive speed device whenever the speed responsive element of said device indicates a predetermined low speed.

9. In an automatic train control system, vehicle carried brake. control apparatus comprising a brake applying device normally controlled by a restrictive speed device,

means for driving said restrictive speed device, when initiated, in accordance with the travel of the vehicle, control means for initiating said restrictive speed device when influences corresponding to unfavorable traffic conditions are received from the track way, and means for causingan immediate op-- eration of said brake control apparatus only if the drive of said restr ctivespeed device stops while the vehicle is under unfavorable for driving said restrictive speed device when 7 initiated, in accordance with the travel of the vehicle, control means for initiating said restrictive speed device when influences corresponding to unfavorable traflic conditions are received from the trackway, other means for causing an immediate operation of said brake control apparatus .if. said drive means be inoperative under unfavorable traffic conditions, and means to prevent such1mmed1- ate brake operation While the vehicle is travelling under favorable traflic conditions.

11. In an automatic train control'system,

vehicle carried brake control apparatus comprising a brake applying device normally controlled by a restrictive speed device, means for driving said restrictive speed device, when initiated, in accordance with the travel of the vehicle, control means for initiating said restrictivespeed device when influences corresponding to unfavorabletraflic conditions are received from the trackway,

means for causing an immediate operation of said brake control apparatus only if said drive means stop under unfavorable traffic conditions, and V automatically operated means to prevent such immediate brake operationif stop of the said drive be due to stopping of the vehicle. 7

12. In an automatic train control system, vehicle carried brake control apparatus comprising a brake applying device normally controlled by a restrictive speed device,

means for driving said restrictive speed device, When initiated, in accordance with the travel of thevehicle, control means for initiating said restrictive speed device when influences corresponding to untavorable tratfic conditions are received from the trackway,

tions and to prevent such immediate brake l operation if the vehicle be travelling under favorable traffic conditions, and automatically operated means to prevent such immediate brake operation if stop of the said drive be due to stopping of the vehicle.

In testimony whereof I aflix my signature.

CHARLES s. BUSHNELL. 

